FLATHEAD LAKE – Flathead Lake researcher Xiong Xiong peers into a clear glass jar filled with water, plant matter and a thin, 3-inch-long piece of plastic. It looks like a bristle from a broom or maybe a piece of fishing line.

Although Flathead Lake is well-known for its brilliantly clear, cold water, unseen pollutants may lurk in the seemingly pristine surface water.

Chinese postdoctoral researcher Xiong is spending a year at the University of Montana’s Flathead Lake Biological Station, working with Director Jim Elser to find out if tiny pieces of plastic are polluting the waters of Flathead Lake, and, if so, how concentrated they are.

Researcher Xiong Xiong takes the first water samples looking for microplastics in Flathead Lake. (UM Photo by Heather Fraley)
Researcher Xiong Xiong takes the first water samples looking for microplastics in Flathead Lake. (UM Photo by Heather Fraley)

“It looks quite clean, but, if this clean lake is suffering from plastics, I want to check that,” Xiong says.

The Trouble with Microplastics

Pieces of plastic smaller than 5 millimeters in size are known as microplastics, which include a wide variety of shapes – from fragments to fibers. One of these types, microfibers, is everywhere. Microfibers can even be found in a polyester T-shirt or fleece coat and carried into the water system after a normal load of laundry.

Plastic does not easily biodegrade. Natural processes break it into smaller and smaller pieces over the years without actually changing the structure. Broken-down plastic still floats around like suds in a bath tub decades after it went into the water.

In his first water sample from Flathead Lake, Xiong found a thin piece of plastic. Although larger than microplastics, bigger plastics also could become a problem, because they eventually break down into microplastics.

Microplastic is a huge pollution problem in water bodies around the world, especially in the oceans, where large piles of garbage accumulate. The largest ocean garbage patch is four times the size of the entire state of Montana in surface area – mostly composed of plastic that is slowly breaking down.

Most microplastic research is done on the ocean.

“I think people think it’s more serious in the ocean, but we want to find the situation in the freshwater inland because many people live inland, and we need the freshwater,” Xiong says. “It may affect our daily life more directly than the plastic in the ocean.”

Xiong’s most recent work, including the work he did for his Ph.D. at the Institute of Hydrobiology, Chinese Academy of Sciences in Wuhan, China, includes testing highland freshwater lakes in the Tibetan Plateau for microplastics. Although a lot less people live on the Tibetan plateau than in the big cities of China, Xiong found the lakes still contain microplastics at concentrations high enough to cause concern. He wants to see if a lake in the sparsely populated Flathead Valley of Montana might carry the same kind of baggage.

Microplastics may absorb toxins, which then can move up through the food chain and end up in fish. Even now, guidelines help regulate how much and what size fish should be eaten from Flathead Lake due to accumulated mercury. The suggested serving-size cards that state and tribal wildlife agencies pass out to anglers don’t factor in potential toxins from plastic.

Not only could microplastics potentially infuse wild-caught food, recent evidence also suggests that plastic particles are making it into commercial, bottled drinking water. Scientists from the State University of New York at Fredonia were commissioned by journalists to test for microplastics in bottled water, and they found them in almost all of the water they tested. The report was released in 2018, and although the study has yet to be peer-reviewed, it’s still indicative of a big problem.

A collection of trash found by Holly Church as she walked along the Flathead Lake shore in May. (UM Photo)
A collection of trash found by Holly Church as she walked along the Flathead Lake shore in May. (UM Photo)

Microplastics already have been found close to home in the Gallatin River in southwest Montana by Adventure Scientists, a nonprofit based in Bozeman. Citizen scientists collected water samples from 70 sites in the Gallatin watershed, revealing plastic pollution.

For his own tests for the presence of microplastics in Flathead Lake, Xiong has gathered water samples from 12 locations around the lake with his windsock-shaped sampling net. He tows the mesh net behind a boat, and it plucks up any particles in the water.

He also has piggy-backed on the long-term data sampling that happens every few weeks in Flathead Lake and its tributaries since the 1970s, known as the Flathead Lake Monitoring Program.

The FMP crew intercepts deposition samples, particles of what falls out of the air before it is deposited in the lake. Xiong has checked some of these samples to see if there are microplastics in them, finding a couple particles that are suspicious under the microscope but nothing definitive. He plans to test both his water and deposition samples in the next couple of months.

To test the samples, Xiong will use hydrogen peroxide to digest the organic matter in the sample, leaving him with only the particles that are suspected microplastics. He will determine if the particles remaining are actually microplastics by testing them with Raman spectroscopy or Fourier-Transform Infrared Spectroscopy.

Both techniques use specific kinds of light sent through the sample. They emit back a unique light pattern that can be used like a forensic examiner uses a fingerprint. This technique can identify the specific substance without destroying the sample.

“If we know what kind of plastics there are, it’s a way for us to find their source,” Xiong says.

The tourism that the Flathead Valley relies on for economic stability could be a factor. Xiong found that tourists were an important source of microplastics in Qinghai Lake, which is the largest lake in China.

Determining something about the source may help reduce the consumption of the most prevalent contributor. If Xiong finds mostly microfibers, the source could be laundry. If he finds particles, it might be bags or bottles.

Xiong hoped in coming to America that people would be more environmentally friendly than they are in China. He was surprised that plastic bags were free at all the stores here.

“In China we have to pay for the plastic bags, so people want to reduce or reuse the plastic bags, but here it’s all free,” he says.

Plastic Problems in the Flathead Valley


FLBS education coordinator Holly Church says she’s equally surprised to see how plastic is used in the Flathead Valley. She helped with an Adopt-a-Highway cleanup effort in front of the bio station in late May.

“I’m horrified how much plastic that is just along our roadways,” she says. “If you just drive anywhere along here, there’s plastic flapping on all the fences. It’s everywhere here.”

The trash along the Highway 35 roadway blows into the lake. Church walked along the shoreline of the lake for a short distance when the water was low and collected a startling amount of trash that had washed up out of the lake – a whole box full, including the cap to a firework rocket, plastic bags, monofilament fishing line and pieces of PVC pipe.

Church also has pulled up plastic in the FMP’s plankton net while out sampling.

Before Church moved to Montana, she lived and worked as a science teacher in California and Hawaii. Both states have taken the initiative to start getting rid of plastic, at least from stores.

Hawaii has gotten on board, because the state is starting to see pretty dramatic effects. Church says she has a handful of “confetti sand” from a beach in Hawaii – a jar of sand mixed with colorful plastic particles.

“I don’t think it’s something that we should continue to have in our environment,” Church says. “Now that we can’t recycle plastic in the valley, it’s even more of an issue. There’s got to be some kind of awareness increase.”

Church plans to set up a citizen science community lake cleanup project based at the bio station to help combat the amount of trash making it into the lake. Germaine White, Confederated Salish and Kootenai Tribes natural resources information and education program manager, said the tribes are hopeful that they can partner with Church in this effort.

Church thinks the community will be quick to pitch in when they become aware of the extent of the issue.

Involving schools in cleanups would raise awareness as well, according to Church. With the bio station’s expanding K-12 education program, there may be room for more pollution awareness in the curricula, since young kids form a lot of the habits they will carry into adulthood.

Church agrees with Xiong that the oceans are receiving most of the attention and would like to see freshwater system receive more awareness – especially since there are far fewer cleanup programs for freshwater systems than for oceans.

Regardless of what Xiong’s findings show when he analyzes his samples, trash that goes into Flathead Lake still can be reduced. Decreasing washes of synthetic clothing, using tie downs or cargo nets to secure items in the back of vehicles or on top of cars, or even grabbing fewer plastic bags at the grocery store are all simple ways to help keep the lake blue and pristine into the future.

For updates and more information about Xiong’s work, visit the FLBS website at https://flbs.umt.edu/newflbs.


By Heather Fraley, UM

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